1. Field of the Invention
The present invention relates to an oxygen generating materials, carbon dioxide absorbing materials, and transport system and transport method of live fishery products for preventing vitality deterioration and death of live fishery products.
2. Description of the Related Art
Methods of transporting live fishery products while keeping the likes of edible natural fish, cultivated fish, shellfish or aquarium fish alive can be divided broadly into transport without using water (which will be referred to as xe2x80x9cwaterless transportxe2x80x9d), transport using tank (which will be referred to as xe2x80x9ctank transportxe2x80x9d), and transport using plastic film bag (which will be referred to as xe2x80x9cplastic transportxe2x80x9d).
Waterless transport is a method wherein fish are transported without using water while being exposed to air, and is used for carp, crucian carp, loaches, prawns and the like. Since it is easy for the fish to fall into a condition of hypoxia, waterless transport can only be used for transports of short periods of time.
Tank transport is a transport method wherein oxygen is supplied from the oxygen cylinder to the water tank installed on a truck while letting the fish swim therein, and is used for transports in large amounts and relatively long distances. However, as this method requires costly specialized equipment, there is a problem in that the usage thereof is limited since transportation expenses become costly.
Furthermore, Japanese Patent Laid-Open Publication No. Hei 4(1992)-26808 proposes a transport method wherein fish, water and oxygen are placed in a receptacle equipped with an air pump and carbon dioxide absorbing tank on the outside while circulating air therein. However, as this method also requires costly specialized equipment, there is a problem in that the usage thereof is limited since transportation expenses become costly.
Plastic transport is a transport method wherein water and live fishery products are placed in a plastic film bag, sealed hermetically while leaving headspace, and further placed in a corrugated cardboard box or the like, and is used for small-scale and short-time transports. Plastic transport is an easy and low-costing method, and is widely used for transporting various kinds of cultivated fish, natural fish and aquarium fish. However, with the plastic transport method, water temperature during transportation, concentration of dissolved oxygen and water quality cannot be controlled, thereby leaving a problem in that, even within a 24-hour transport, vitality deterioration and death of fish during transport are likely to occur.
Therefore, with plastic transport, various ideas such as lowering the temperature of water that is hermetically sealed together with the fish, filling the headspace with gaseous oxygen, and ceasing the provision of feed have been employed in order to prevent vitality deterioration and death of fish during transport.
However, the employment of these methods is still usually insufficient in preventing vitality deterioration and death of live fishery products during the transport thereof. Particularly during the summer season when the temperature rises, vitality deterioration and death of fish occur, thereby leaving a problem in that the product value of such live fishery products being significantly reduced. With respect to edible fish, the price of dead fish is reduced to less than half of that of live fish. This is even a more serious problem concerning aquarium fish, whereby an aquarium fish that dies during transport becomes valueless. Furthermore, even if the fish loses vitality or a single fish inside the transport bag is to die, there is a problem in that the product value will be significantly reduced.
Particularly, transports to distant places requiring 24 hours or more is extremely difficult with conventional plastic transport technology as vitality deterioration and death of fish are likely to occur.
Moreover, as oxygen generating materials to be used for the transport or the like of live fishery products, a type wherein an aqueous solution of peroxide and a decomposition agent thereof are packaged with a multi-layered package (Patent Laid-Open Publication No. Hei 1(1989)-103902), a type wherein peroxide and the like are covered with a water-permeable sheet including a layer of active carbon (Patent Laid-Open Publication No. Hei 5(1993)-306104), and a type wherein a composition of hydrogen peroxide adduct and the like and a solidifying agent are packaged (Patent Laid-Open Publication Hei 7(1995)-289114) and so on have been proposed. However, a type which fulfills all such conditions as no elution of composition components into the water upon usage, easy operation, steady generation of oxygen for a long period of time, low manufacturing cost, and outstanding preservation stability has not been provided heretofore.
The present invention aims at solving the aforementioned conventional problems and an object thereof is to provide a low costing oxygen generating materials and carbon dioxide absorbing materials without requiring special equipment or machinery and having a simple structure with the operation being easy, wherein the oxygen absorbing materials are capable of generating oxygen for a long period of time in a safe and steady manner.
Another object of the present invention is to provide a transport system and transport method of live fishery products utilizing such oxygen generating materials and carbon dioxide absorbing materials.
In order to achieve these objects, upon intense study to solve such problems, the inventors have reached the present invention by discovering that the oxygen generation speed could be controlled by adjusting the amount of moisture to come in contact with a specific oxygen generating materials.
In addition, the inventors have reached the present invention by discovering that the oxygen generation speed and preservation stability could be controlled by adjusting the particle diameter of active carbon in an oxygen generating materials, which is formed by packaging peroxide and active carbon with a water-resistant moisture-permeable material.
Furthermore, the inventors have reached the present invention by discovering that a carbon dioxide absorbing materials, which is formed by packaging alkaline earth metal hydroxide and/or oxide with a plastic gas-permeable material having a Gurley method gas permeability (JIS P8117) of 0.1xcx9c3000 sec./100 ml of gas and being impervious to water at normal pressure, efficiently absorbs carbon dioxide and effectively controls the increase of the carbon dioxide concentration.
Moreover, the inventors have reached the present invention by discovering that using an oxygen generating materials and carbon dioxide absorbing materials jointly together within a transport bag prevents vitality deterioration and death of live fishery products and extends the transport time thereof.
Particularly, the present invention provides an oxygen generating materials which is prepared by packaging solid peroxide and peroxide decomposition catalyst with a moisture-permeable material having a cup method moisture permeability (40xc2x0 C., 90% RH) of more than 20 g/m2/24 hr and being impervious to water at normal pressure.
Peroxide decomposition catalyst may be composed of at least one type selected among manganese dioxide, active carbon, and catalase.
Furthermore, active carbon having a average particle size of 25xcx9c5000 xcexcm may be used.
Moisture permeating material may be composed of a multi-micropores film made from a plastic sheet.
Furthermore, moisture permeating material may be composed of a non-woven fabric made from a plastic sheet possessing micropores.
Solid peroxide may be composed of at least one type selected among sodium carbonate hydrogen peroxide adduct, sodium perborate mono-hydrate, and sodium perborate tetra-hydrate.
The weight ratio of solid peroxide and peroxide decomposition catalyst may be 100:0.01xcx9c100:100.
Moreover, the present invention comprises alkaline earth metal hydroxide and/or oxide and a gas-permeable material having a Gurley method gas permeability (JIS P8117) of 0.1xcx9c3000 sec./100 ml of gas and being impervious to water at normal pressure, and provides a carbon dioxide absorbing materials which is prepared by packaging alkaline earth metal hydroxide and/or oxide with a plastic gas-permeable material.
Alkaline earth metal hydroxide and/or oxide may be selected among calcium hydroxide, magnesium hydroxide, calcium oxide, and magnesium oxide.
Gas permeable material may be a plastic microporous film.
Furthermore, gas-permeable material may be a plastic non-woven fabric.
Furthermore, the present invention provides an oxygen generating materials/carbon dioxide absorbing materials package that is prepared by packaging an oxygen generating materials and carbon dioxide absorbing materials with a packaging material which permeates water at normal pressure. This packaging material which permeates water at normal pressure may be composed of hydrophobic non-woven fabric.
Furthermore, in the present invention, it is possible to add a desiccant to the oxygen generating materials and carbon dioxide absorbing materials. Although there is no particular limitation regarding the type of desiccant to be placed within the oxygen generating materials package, upon considering the performance and convenience in handling the same, it is preferable to use at least one type selected among silica gel, activated alumina, and zeolite. Although it may differ according to the type and water content percentage of solid peroxide and catalyst, type of desiccant, moisture permeability and preservation condition of the packaging material, the most preferable weight ratio of solid peroxide and the desiccant is within the range of, generally speaking, 100:0.1xcx9c100:100. By providing a desiccant within the oxygen generating materials package, the moisture concentration within the package is preserved low, stability of peroxide upon preservation is increased, and collapse of loads caused by inflation of the preservative outer bag is prevented.
As desiccants to place within the carbon dioxide absorbing materials package, the same desiccants used in the oxygen generating materials package may be utilized. By providing a desiccant within the carbon dioxide absorbing materials package, the moisture concentration within the package is preserved low, and the stability of alkaline earth metal hydroxide upon preservation is increased.
It is preferable that this oxygen generating materials/carbon dioxide absorbing materials package with the added desiccant be preserved within an outer bag made from non moisture-permeable material having a cup method moisture permeability (40xc2x0 C., 90% RH) of less than 20 g/m2/24 hr. As non moisture-permeable material, it is possible to use the likes of aluminum foil, aluminum evaporation film, silica evaporation film, polyvinylalcohol film, non-permeable nylon film, and polyvinylidene chloride coated film.
Making the outer bag made from non moisture-permeable material a hermetically sealed bag is preferable in that seepage of moisture from the outside may be restrained and thereby displaying significant advantages of the desiccant within the oxygen generating materials. Moreover, in order to avoid the inflation of the outer bag when oxygen is generated upon a portion of peroxide being decomposed, it is preferable that a pinhole be provided on the outer bag. In such case, in order to absorb the small amounts of moisture seeping through such pinhole from the outside, a desiccant may further coexist within the outer bag.
Furthermore, the present invention provides a transport system of live fishery products wherein an oxygen generating materials and carbon dioxide absorbing materials are sealed inside a transport bag.
The oxygen generating materials may be prepared by packaging solid peroxide and peroxide decomposition catalyst with a moisture-permeable material having a cup method moisture permeability (40xc2x0 C., 90% RH) of more than 20 g/m2/24 hr and being impervious to water at normal pressure.
The carbon dioxide absorbing materials may be prepared by packaging alkaline earth metal hydroxide and/or oxide with a plastic gas-permeable material having a Gurley method gas permeability of 0.1xcx9c3000 sec./100 ml of gas and being impervious to water at normal pressure.
Furthermore, solid peroxide may be composed of at least one type selected among sodium carbonate hydrogen peroxide adduct, sodium perborate mono-hydrate, and sodium perborate tetra-hydrate.
Furthermore, peroxide decomposition catalyst may be composed of at least one type selected among manganese dioxide, active carbon, and catalase.
Furthermore, alkaline earth metal hydroxide and/or oxide may be selected among calcium hydroxide, magnesium hydroxide, calcium oxide, and magnesium oxide.
Furthermore, the present invention provides a transport system of live fishery products wherein an oxygen generating materials according to the present invention is sealed inside a transport bag.
Furthermore, the present invention provides a transport system of live fishery products wherein a carbon dioxide absorbing materials according to the present invention is sealed inside a transport bag.
Furthermore, the present invention provides a transport system of live fishery products wherein an oxygen generating materials are sealed inside a transport bag containing live fishery products and liquid for such live fishery products to be kept alive.
Furthermore, the present invention provides a transport system of live fishery products wherein a carbon dioxide absorbing materials are sealed inside a transport bag containing live fishery products and liquid for such live fishery products to be kept alive.
Furthermore, the present invention provides a transport system of live fishery products wherein an oxygen generating materials and carbon dioxide absorbing materials are sealed inside a transport bag containing live fishery products and liquid for such live fishery products to be kept alive.